requires
bioluminescense ______ a great amount of energy
vibrio fischeri
only release their light when it is inside the light organ of squid
quorum sensing
how v. fisheri regulate light production.
autoinducer
small nonpolar signal molecule that is made in the cytoplasm of v. fischeri and diffuses across the plasma membrane
high
autoinducers accumulate at _____ density in the light organ of the squid and diffuse back into the cytoplasm of the cell
receptor; gene regulated protein
autoinducer binds to a _____ and a ________ after diffusing back into cytoplasm of the cell
receptor autoinducer
_____:______ complex binds to the promoter of the luciferase genes
RNA poly
receptor recruits ______ to result in luciferase expression
cell cell signaling types
contact dependent, paracrine, synaptic, endocrine
contact dependent signaling
one cell signals to immediate neighbor using cell surface signal molecules and receptors
paracrine signaling
signal molecule is senses by cells in immediate vicinity of signaling cells
synaptic signaline
mechanism for cell cell signaling used by neurons
endocrine signaling
signal molecule is released by endocrine cells into bloodstream, which disperses the signal to other targets
intracellular
in oder to bind to _________ receptors, signal molecule must be small and hydrophobic enough to pass through the plasma membrane and bind
cell surface receptors
these types of receptors are attached to signal molecule in the plasma membrane
they control intracellular signalling proteins which can alter cell behavior
steroid
hydrophobic signal molecules synthesized from cholesterol
intracellular receptors
steroids are a type of signaling molecules that activate ________
open
without steroid attached, the receptor is in an _____ conformation that won't bind to DNA or activate transcription
steroid
______ binding causes closing of receptor around the steroid molecule
conformation
receptor:steroid complex can bind to DNA once the ________ changes
coactivator proteins
these bind to induce transcription of ..?
phosphorylation and GTP binding
turn on and off signaling proteins
protein kinase
enzyme that covalently attach phosphate to other proteins
phosphorylation
normally activates signaling protein
phosphatase
removes the phosphate from signaling protein
binding
GTP ______ activates signaling protein
hydrolysis
GTP ______ inactivates the signalling protein
cell surface receptor classes
ion channel coupled receptors
enzyme coupled receptors
g protein coupled receptors
ion channel coupled receptors
neurotransmitter gated ion channels
enzyme coupled receptors
enzyme is either the receptor or the receptor associated enzyme. binding of signaling molecule activates an intracelular catalytic domain
g protein coupled receptor
signal molecule binds and causes activation of a GTP binding protein
activates
GTP binding protein diffuses in the membrane to ______ a signaling enzyme
function; abundance
signaling pathways alter cell behavior by changing protein _____ and ______
speed; durability
_____ and ______ determine which strategy is used for cell signaling
slow
______ responses rely on changes in gene expression; time required for transcription/translation slows down behavior
slow
_______ responses are durable and last longer
fast
______ responses rely on altered protein function
fast
_____ responses fade rapidly once the signal is gone
active
____ form of many intracellular signal molecules has a short survival time
too stable
is signaling molecule is __________, the response will persist even after signaling has stopped
short half life
molecules with a _____ _____ ______ will allow signalling to stop rapidly - aka rapid response
rapidly
signaling events that require rapid responses involve proteins that are ____ turned over/activated
scaffold proteins
attach to receptors to help cells avoid crosstalk between signaling pathways
inactive
______ intracellular signaling proteins assemble on scaffold protein
signaling complex
when signal is received by receptor, it is relayed from one signaling protein to the next via ____ ______ (for scaffolding protein)
signaling complex
ensure rapid signal delay and prevent cross talk
inactive
some intracellular signal proteins are free in cytosol when receptor is ______
receptor phosphorylation
provides docking sites for intracellular signal proteins that relay signals to downstream targets
phosphoinosides
generate docking sites for some signaling complexes
phosphorylated
once phosphoinositides are _______, they can allow signaling complexes to form on the membrane
integration
multiple signals can impinge on one protein via _______
modular interaction domains
phosphotyrosine binding domain, src homology 2, pleckstrin homology, src homology 3
PTB domain
attaches to phosphorylated tyrosine residues on activated receptors
SH2 domain
binds to phosphotyrosine
PH domain
attaches to particular phosphoinositides on the inner leaflet of the plasma membrane
SH3 domain
binds to other proteins to assemble signaling complexes
domain combination
______ ________ dictates which proteins the signaling protein binds and therefore the role of the signaling protein
amino acids
each SH2 binds to phosphotyrosine and _______ of the protein that it recognizes
phosphorylation
many signaling proteins have several SH2 domains that only recognize specific protein ________ patterns
JAK
cytokine receptors attach to ______
dimerization
cytokine binding induces receptor ____
trans phosphorylation
receptor dimerization triggers _______ ________ of JAK
JAk
phosphorylates cytokine receptor
STAT
binds receptor with SH2 domains and becomes phosphorylated
STAT
dissociates and dimerizes using SH2 domains
STAT dimer
induces expression of genes that help fight expression upon being transferred into the nucleus
JAK STAT
signaling that is important to the immune system
autoimmune disease
diseases that result from unregulated immune response
tofacitinib
JAK inhibitor that enters T cells and binds to JAK and shuts down JAK STAT signaling
nonreceptor tyrosine kinase
kinases that signal via JAK STAT pathway
receptor tyrosine kinase
kinases that are part of the receptor of cytoplasmic domain
dimerizes
in RTK, signaling molecule binding ____ the receptor
crossphosphorylate
in RTK, receptor monomers __________ to initiate signaling
EGF
epidermal growth factor ; mitogen
growth factor
control cell growth by regulating protein synthesis
mitogen
stimulate mitosis
EGF
binds and activates the epidermal growth factor receptor
phosphorylated
when EGF binds to EGFR, EGFR is _______
Grb2
docks at the EGFR phosphototyrosine using SH2 domain
Sos
Ras GEF that is bound to Grb2 via SH3 domain
GDP; GTP
Sos activates Ras by catalyzing _____ to ______ `
MAP kinase cascade
major target of Ras:GTP
Ras:GTP
this complex activates Raf kinase
Raf
phosphorylates the Mek kinase
Mek
phosphorylates Erk kinase
Erk
phosphorylates and activates downstream regulators of mitosis
macrophages
MAP kinase signaling is required for survival of ______
PI phosphorylation
carried out by PI kinases and generates phospoinositides
phosphoinositides
PI with phosphate at one or more carbons of the inosol head group
PI3 kinase
phorphorylates phosphatidylinositol at 3rd , 4th, and 5th positions
important for cell survival
tyrosine
survival factor binds receptor ______ kinase
PI3 kinase
recruited by phosphorylated receptor that has survival factor bound to it
bcl2
bad inactivation causes release of the apoptosis inhibitor ____
GPCR
largest family of cell surface receptors in eukaryotic cells
GPCR
membraneproteins with 7 alpha helical transmembrane domains
trimeric
G proteins are _____
alpha
_____ subunit is the GTP-binding domain in G protein coupled receptors
beta; gamma
_____ and _____ subunits control signalling in G protein coupled receptors
trimeric G proteins
are anchored to inner leaflet of plasma membrane via lipid modification of alpha and gamma subunits
loosely attached
in absense of extracellular signal molecule, GPCR is _____ _______ to an inactive trimeric G protein
extracellular signal molecule
_____ ______ ______ binds to extracellylar domain of GCPR after the inactive G protein is bound to GDP
alpha subunit
GPCR activates the _______ of the trimeric G protein
GEF
activation of GPCR causes ____ so that the alpha subunit can bind to GTP
beta gamma
activated alpha subunits can activate the _____ subunit of G protein
cAMP
synthesized from ATP by adenylate cyclase
cAMP
type of second messenger in cells
Gs
trimeric G protein that stimulates cAMP production
Gi
trimeric G proteins that inhibit cAMP production
AMP
when signaling is finished, cAMP phosphodiesterase cleaves cAMP to ____
adenylate cyclase
converts ATP to cAMP
high
_____ cAMP = electrolyte and fluid loss
cAMP
controls fluid balance across epithelial cells
pertussis toxin
inactivates Gi and causes host cell to increase adenylate cyclase activity and cAMP
ACase
bacterial adenylate cyclase that enters the cells and raises cAMP
Ptx and ACase
toxins produced from whooping cough; trigger increase cAMP in respiratory epithelials cells that lead to fluid loss
Gq
G proteins that signal through the enzyme phospholipase C
IP3 and DAG
products of PI(4,5)P2
IP3
phosphate that is soluble in the cytoplasm of the cell
diffuses away from the membrane and takes part in downstream signaling events
DAG
triggers downstream signaling events
calmodulin
Ca2+ regulated signaling protein that has two globular domains connected by an alpha helix
T cells
cells of the immune system rely on calmodulin signaling
antigen
when T cell meets _______, it produces the signaling molecule interleukin 2
NFAT
binds DNA at the promotor for IL2 gene and allows cell to express IL2 which elicits cell division
cyclosporin A
immunosuppressive drug
proteolysis
cell cell signaling event where receptor typically signals for the cleavage and/or degradation of a cellular protein
lateral inhibition
process where cells block each other from developing into the same cell type
delta
when activated by _____, notch blocks cell specialization
notch
represses expression of delta
delta
the _____ expressing cell will develop into specialized nerve cells
NFkB
proteolytis regulated signaling that is initiated by the signaling protein tumor necrosis factor alpha
TNFalpha
major signaling protein involved in triggering inflammation as response to infection
released by macrophages upon infection
is a trimer